The night fae of this realm seem unable or unwilling to provide details that might substantiate my theory, though I did locate one source who, when pressed, admitted to having overheard the Winter Queen refer to a certain Life-bound entity as her sister, a familial term that would seem ill fitting when used in reference to a being who is directly contrary to her very nature. Yer just as the Winter Queen assumed her place in the Pantheon of Death, this apparent counterpart took up a similar position in what we must hypothesize to be a Pantheon of Life.
Whatever relationship might have once existed between the two "siblings" whose bond was fundamental to the eternal cycle between Death and Life seems to have been all but severed. For how could even two figures of such unimaginable power commune across the veritable chasm that separates their disparate planes of existence? It is said (only in hushed whispers, I assure you) that in the eons that followed their parting, signs of resentment and pain began to mar the placid visage of the Winter Queen, especially when she heard the nage of her sister uttered within her forest. Even her recent action to save Ysera betrays those emotions,for I am told that the Winter Queen seemed to show a moment of hesitation before making the sacrifice required to save the soul of the dragon so dear to the one she resented. Yet it must be said that the truth of these matters exists solely within the Winter Queen herself, and to ask the inscrutable Enternal One for answers would be a fool's errand indeed.